SolarCity Gives Light Year New Meaning

The lessor of solar-power panels to homeowners has a highflying stock, but its optimistic outlook is based on a lot of long-term assumptions.

Even as the market rockets to the heavens, some stocks make it look like it's standing still. SolarCity is one of them.

Friday's closing price of $77.80 valued the San Mateo, Calif.-based company at nearly $6.5 billion—a tenfold increase from the stock's initial offering in 2012 and more than double its level when Barron's reported a dispute over SolarCity's federal subsidies ("Dark Clouds Over SolarCity," Sept. 2,...